This invention relates to a method of isotope separation and enrichment, and more particularly, to a method of photochemical dissociation to obtain hydrogen isotopes.
It is well known in the art that lasers may be used to selectively induce chemical reactions which effectively result in isotope separation or enrichment. N. V. Karlov, Applied Optics, Vol. 13, Page 301 (1974) in an article "Laser Induce Chemical Reaction" teaches the utilization of infrared radiation from a high power carbon dioxide laser to excite vibrational energy levels of a particular chemical bond of a selective polyatomic molecule within a sample while simultaneously irradiating the sample with laser radiation in the visible or near ultraviolet spectrum to obtain dissociation. The interaction of the infrared radiation with the molecule produces a cascading excitation of the vibrational energy levels of a selective chemical bond. The article teaches that molecules capable of resonant intractions with carbon dioxide laser radiation include SF.sub.6, BCL.sub.3, NH.sub.3, N.sub.2 F.sub.2, PF.sub.5, SiH.sub.4, methyl alcohol CH.sub.3 OH, a group of halogen-substitute methanes CH.sub.3 F, CH.sub.3 CL, CH.sub.3 Br, ethylene C.sub.2 H.sub.4 and formaldehyde H.sub.2 CO.
Robinson et al in U.S. Pat. No. 4,049,515 filed Apr. 22, 1975 discloses a method of obtaining elements enriched in a particular isotope by irradiating a fluid having two or more isotopes of an element with infrared laser radiation having a frequency which vibrationally excites to a first lower vibrational energy level only those molecules of a particular isotope of the element. The intensity of the laser radiation must be sufficient to obtain multiple photon absorption within the first lower vibrational energy level resulting in populating a plurality of higher vibrational energy level by a cascade process until photodissociation occurs. In particular, the patent teaches the utilization of the method to obtain BCL.sub.3 highly enriched in .sup.10 B by irradiating a mixture of natural BCL.sub.3 and hydrogen gas with an intense beam of pulse CO.sub.2 radiation. Also, SF.sub.6 highly enriched in .sup.34 S is obtained by irradiating a mixture of natural SF.sub.6 and hydrogen gas with an intense beam of pulsed carbon dioxide laser radiation.
Marling in U.S. Pat. No. 4,029,557 filed June 17, 1976 discloses the enrichment of carbon, hydrogen and/or oxygen isotopes by means of isotopically selective photo-predissociation of formaldehyde by irradiation with a fixed frequency ion laser.
A method of utilizing an efficient source of laser radiation to dissociate hydrogen isotopes from naturally occurring compounds without requiring laser radiation at two wavelengths is desired. Naturally occurring compounds have an abundance ratio of deuterium to hydrogen in the order of about 1.5.times.10.sup.-4. Thus the utilization of naturally occurring compounds has the potential for producing an abundant supply of processable deuterium.